This SBIR Phase I proposal seeks support for the development of a rapid, low-cost, highly-sensitive endotoxin detection system. Utilizing the viscosity-monitoring capabilities of the magnetoelastic sensor, this system magnetically determines the endotoxin level by measuring the gel formation in Limulus Amoebocyte Lysate (LAL) assay, a popular assay derived from horseshoe crabs for endotoxin quantification. Ribbon-like magnetoelastic sensors, made of anamorphous ferromagnetic alloy, are remotely interrogated via magnetic fields. This passive sensor technology is ideal for detecting coagulation of the LAL assay since its resonance behavior is largely dependent upon medium viscosity. Preliminary studies have shown that the resonance amplitude of the magnetoelastic sensor decreases during the coagulation of the LAL assay, and the magnitude of the time rate of change is proportional to the endotoxin concentration. The work builds upon, and parallels, Sentechs' development of a heparin management system, per determination of activated clotting time, using magnetoelastic sensors. The focus in Phase I is to develop the endotoxin detection device and optimize its performance. Specifically, in Phase I we will: {1} Further miniaturize and optimize the sensors to reduce the amount of LAL assay needed. {2} Refine the sensor reader electronics, extending the upper frequency operational limit and including an additional 40dB of gain. {3} Design and fabricate the pyrogen-free LAL-mixing disposable package for the sensor and the sample collection apparatus. {4} Develop an algorithm to accurately calculate the endotoxin level based on the sensor response to enable endotoxin quantification in but a few minutes time. It is our objective to show that the proposed low-cost sensor system outperforms current leading technologies, greatly facilitating early detection of endotoxin infections and thereby reducing the sepsis mortality rate. The motivation behind this project is to significantly reduce the rate of sepsis mortality by providing healthcare providers an accurate, inexpensive, and rapid tool for detecting endotoxic infections in high-risk patients, especially those within intensive care units. Annually in the U.S. there are 750,000 cases of sepsis (more than 50% are due to endotoxin infections) that result in over 200,000 deaths. Consequently we believe the success of this project will make a significant contribution in improving public health. [unreadable] [unreadable] [unreadable]